Abstract: A tamper resistant package is disclosed which comprises a container having a closed end, at least one side wall, and an open end defined by the side wall, the side walls having radially extending sealing surfaces, and a closure of plastic material such that the closure flexes in thin cross section. The closure has a depending annular skirt which is adapted to securely fit within the open end of the container. The depending annular skirt defines radially extending sealing surfaces for engaging the radially extending sealing surfaces of the container and for placing the container and closure under tension to secure the closure on the container. The closure is snapped into the open end of the container and is sealed under tension such that an attempt to disengage the closure from the container causes visual damage to either the closure or the container which can be seen by observing the package from the top. The tamper resistant package is especially useful for conducting urine specimen testing procedures.